Hearth



May 28, 1946. D. c. CAMPION 2,4015227 HEARTH File d Nov. 29, 1944 2Sheets-Sheet 2 IN VEN TOR;

I Dana/0 CZ Camp/on I Patented May 28, 1946 UNITED STATES- PATENT OFFICEHEARTH Donald 0. Campion, Detroit, Mich. Application November 29, 1944,Serial No. 565,659

12 Claims.

This invention relates to a hearth and more" particularly to a hearthfor a heat treating furnace.

It is anobject of this invention to produce a hearth for a heat treatingfurnace which is admirably adapted for a pusher type furnace wherei .1

in the stock being heat treated is pushed along the hearth,

The invention contemplates a hearth made from a high temperature alloywhich can be easily assembled, disassembled and repared, which l is longlived, and which will withstand expansion and contraction due to thermalchanges and temperature differences in different areas of the hearthwithout buckling.

These objects are achieved by fabricating the F1 hearth from a pluralityof identical or similar sections or railsof a high temperature alloy andwhich are connected together by interlocking members which permitsufiicient longitudinal and lateral movement by the rails to take careof the incidental rails. and a dotted line showing of one of the f railsin position for disengagement,

Referring more particularly to the drawings it will be seen that myhearth comprises a plurality of interengaged rails each having anelongated body I. Body I can have an inverted V cross-section or can befiat'in cross-section. The

rail with an inverteclv cross-section is preferable in a pusher typefurnace whereas rails which are much wider than the V rails and whichhave a flat surface instead of a peak are preferably used as a floor ina batch type furnace where the stock is shoveled or thrown into thefurnace. Bails I are made of any suitable material having high strengthat high temperatures, but preferably are made from an alloy having highstrength at high v temperatures such as are encountered in heat"treating furnaces.

Rail I, when assembled in the hearth, is arranged with the apex of the Vup so that in cross section the rail takes the form of aninverted VSince my hearth is arranged to over-- lay or be set upon the furnacehearth 2, which is a refractory material or clay that can be easilydamaged, I provide each rail of my hearth with four legs 3 which havefiat and horizontal ho tom faces 4 which rest upon the refractory hearth2 and distribute the weight of the work over a substantially large area.If the edges of the inverted V rails were not provided with the fiatsupporting legs or bearing surfaces 4, they would dig into and destroythe refractory hearth 2. It will be noted that these supporting legs 3on opposite sides of each rail I are offset from each other.

Each rail is provided with a. plurality of integral interlocking membersor fingers .5 of V section. Fingers 5 on one side of rail I are ofisetfrom the fingers 5 on the opposite side of the rail. Fingers 5 and legs3 on each side of the rail are spaced a distance greater than the lengthof I fingers 5 and legs 3. Fingers 5 and legs 3 are approximately thesame length. The spaces between fingers 5 and legs 3 are referenced 6.The length of space 6 should be greater than the length of either legs 3or fingers 5 in an amount sufficient to care of longitudinal expansionand contraction of the rails due to temperature variations. For purposesof description and not by way of limitation, space 6 can be a quarterofan inch longer than leg 3.

In use the rails are setupon a refractory hearth 2 with the apex of therail uppermost. Rails I are mounted in parallel rows and staggered sothat the joints 1 in alternate rows are aligned and the jointsinadjacent rows are offset. The interlocking of the rails are effected byfingers 5 which interengage the underside of body I. Each finger 5 onone rail fits into a space or slot 6 in the adjacent rail between afinger 5 and a leg 3. Thus, the interlocking of fingers 5 on theunderside of body I holds the rails against lateral dislacement and theinterengagement of fingers 5 on the one rail in slots 6 between a finger5 and a leg 3 on the opposite rail holds the rails from pulling apartlengthwise. The interlocking fit between the fingers of one rail and theunderside of the adjacent rail is loose so as to permit longitudinal andlateral movementof the rails relative to each other caused by thermalexpansion and contraction without buckling. Each leg 3 on the one railalso interengages between a leg and finger on the adjacent rail. Myhearth is generally designated 8. The end sections in alternate rows ofrails can be any length that permits staggering of the joints and inmost cases the end sections will be one-half the length of the otherrail sections. This is necessary in order to position joints 1 as abovedescribed.

To disconnect one rail from the other it is necessary to hinge or swingthe one rail upwardly about the hinge provided by the interconnectedfingers and legs of the adjacent rails. By swinging one rail upsufiiciently, fingers 5 simply slide or swing out of interengagementwith the underside of the adjacent rail (Fig. 8).

It will be seen that the full length rail comprises two fingers 5 andtwo legs 3 on each longitudinal side of the rail. In fabricating thehearth, in order to offset joint ,1, a half length of rail l is used ateach end of alternate rows of rails.

The rails l cooperate to form a track along which the work can he slidthrough a heat treating furnace, for example, adjacent rails I beinginterlocked cooperate to form a groove or track along which the work canbe slid and the interconnecting fingers 5 and legs 3 keep the hearthfrom separating either laterally or lengthwise of hearth members in theadjacent row, the hearth members in each row being interengaged with themembers in the adjacent row so that the members in each row can move alimited distance relatively to each other and relative to the members inthe adjacent row without buckling the hearth where the movement is suchas is occasioned by expansion and contraction caused by thermal changes.

stantially the form of an inverted V projecting downwardly and thenupwardly from the other longitudinal edge of the rail and ofiset fromthe said support leg, the said support leg being adapted forinterengagement with the underside of an adjacent rail of substantiallythe same form and the support leg being adapted to support the rail andto rest under and support an adjacent rail of substantially the same,form as the rail herein claimed.

7. A hearth member comprising a rail in substantially the form of aninverted V having at least one support leg projecting downwardly andthen outwardly in a substantially horizontal plane from oppositelongitudinal edges of the rail, the leg on the one side being spacedlongitudinally from the leg on the other side of the rail, and at leastone locking finger projecting downwardly and then upwardly from theopposite longitudinal edges of the rail, the locking finger on the oneside being spaced longitudinally from the locking finger on the otherside of the rail, the locking finger and support leg on each side of therail being spaced from each other a distance sufficient to accommodatetherebetween the locking finger and support leg of a rail of similarshape.

8. A hearth member comprising a rail having a cross sectionsubstantially in the form of an inverted V, said rail having on eachside a sup- 2. A hearth comprising in combination a plu- 7 j rality ofparallel rows of hearth members,'each hearth member having substantiallythe form of an inverted V, the members of each row being in substantiallongitudinal alignment and offset longitudinally with respect to thehearth mem 7 bers in the adjacent row, the hearth members in eachrowhaving fingers which underlie and interengage the undersides of thehearth members in the adjacent row when the adjacent hearth members arein substantially the same plane whereby the hearth members can bedisengaged byhinging the hearth members in the one row upwardly abouttheadjacent lower edge of the hearth members in an adjacent row.

3. The combination as set forth in claim 2 wherein the hearth membersare provided along 'move longitudinally only a limitedrdistanc e.

4. A rail for a hearth comprising abody portion in, the form of aninverted V having a leg projecting downwardly and outwardly from onelongitudinal edge of the rail, and a locking finger projectingdownwardly and then upwardly from the oppositeedge of the rail.

5. The combinationfas set forth in claim 4 wherein the locking fingerand the supporting leg are ofiset from each other lengthwise of the'rail.

6. A rail for a hearth comprising a body portion in the form of aninverted V having a leg projecting downwardly and outwardly in asubstantially horizontal plane from one longitudinal edge of the rail,and a locking finger in subport leg projecting downwardly and thenoutwardly in a substantially horizontal plane from' the lower edge ofthe rail, and a locking finger projecting downwardly and then upwardlyfrom the lower edge of the. rail, the locking finger and support leg onone side of the rail being offset from the locking finger and supportleg on the opposite side of the rail, the locking finger and support legon each side of the rail being spaced lengthwise of the rail a distanceslightly greater than the length of the locking finger or leg wherebytwo of said rails are adapted to be interengaged by inserting thelocking fingers and support legs of one rail in the spaces between thelocking fingers and support legs of the other rail so that the rails canmove a limited distance longitudinally of each other such as isoccasioned by expansion and contraction due to temperature changeswithout binding.

9. A hearth member comprising a rail having on each side a support legprojecting downwardly and then outwardly in a substantially horizontalplanefrom the lower edge of the rail, and a locking finger projectingdownwardly and then upwardly from the lower edge of the rail. thelocking finger and support leg on one side of the rail being ofiset fromthe locking finger and support leg on the opposite side of the rail, thelocking finger and support leg on each side of the rail beingspacedlengthwise of the rail adistance slightly greater than the length of thelooking finger or leg whereby two of said rails are adapted to beinterengaged by inserting the locking fingers and support legs of onerail in the spaces between the locking fingers and support legs of theother rail so that the rails can move a limited distance longitudinallyof each other such as is occasioned by expansion and contraction due totemperature changes without binding.

10. A hearth comprising in combination a plurality of parallel rows ofhearth members, the members of each row being in substantiallongitudinal alignment anad offset longitudinally with respect to thehearth members in the adjacent 3:} row, the hearth member in each rowhaving fingers which underlie and interengage the undersides of thehearth members in the adjacent row when the adjacent hearth members arein substantially the same plane whereby the hearth members can bedisengaged by hinging the hearth members in the one row upwardly aboutthe adjacent lower edge of the hearth members in an adjacent row, thehearth members being provided along their lower edges with support legsspaced from the locking fingers whereby a support leg of one hearthmember will fit beneath the adjacent edge of a hearth member in anadjacent row and between a locking finger and a support leg of suchhearth member in an adjacent row whereby the locking fingers and supportlegs of

